In Episode 19 - The Lugru Corridor, Kirito and Leafa are blocked from entering Lugru by Salamanders and are forced to fight with them. In the middle of the fight, Yui tells Leafa to use all her magic to heal Kirito from the damage of the incoming barrage of Fire Spells, while Kirito is chanting an Ilusion Spell that Leafa taught him when they entered the corridor.
Kirito turns into The Gleam Eyes from Sword Art Online and begins to kill everyone (save one Salamander who Kirito then bribes with the loot he just got, while another fled by diving into the lake, only to die).
Leafa explained previously that Spriggan's spells are mostly useless in battle, and by definition Illusions shouldn't damage enemy players or even kill them (unless they are intimidated and back off falling into an abyss of a monster filled lake). If they could do damage, they'd technically be summoning/conjuring.
Kirito isn't a hacker who made Leafa, Yui and all the Slamanders think that a giant beast was throwing them about, when really he was just stabbing them. And in Sword Art Online, Kirito didn't have any sort of summoning abilities (at least in the anime). So how did Kirito's Illusion pick up, throw and kill the Salamanders?